TY  - JOUR
A1  - Dehm, Daniel
A1  - Krumbholz, Julia
A1  - Baunach, Martin
A1  - Wiebach, Vincent
A1  - Hinrichs, Katrin
A1  - Guljamow, Arthur
A1  - Tabuchi, Takeshi
A1  - Jenke-Kodama, Holger
A1  - Süssmuth, Roderich D.
A1  - Dittmann-Thünemann, Elke
T1  - Unlocking the spatial control of secondary metabolism uncovers hidden natural product diversity in nostoc punctiforme
JF  - ACS chemical biology
N2  - Filamentous cyanobacteria belong to the most prolific producers of structurally unique and biologically active natural products, yet the majority of biosynthetic gene clusters predicted for these multicellular collectives are currently orphan. Here, we present a systems analysis of secondary metabolite gene expression in the model strain Nostoc punctiforme PCC73102 using RNA-seq and fluorescence reporter analysis. Our data demonstrate that the majority of the cryptic gene clusters are not silent but are expressed with regular or sporadic pattern. Cultivation of N. punctiforme using high-density fermentation overrules the spatial control and leads to a pronounced upregulation of more than 50% of biosynthetic gene clusters. Our data suggest that a combination of autocrine factors, a high CO2 level, and high light account for the upregulation of individual pathways. Our overarching study not only sheds light on the strategies of filamentous cyanobacteria to share the enormous metabolic burden connected with the production of specialized molecules but provides an avenue for the genome-based discovery of natural products in multicellular cyanobacteria as exemplified by the discovery of highly unusual variants of the tricyclic peptide microviridin.
Y1  - 2019
U6  - https://doi.org/10.1021/acschembio.9b00240
SN  - 1554-8929
SN  - 1554-8937
VL  - 14
IS  - 6
SP  - 1271
EP  - 1279
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Burek, Katja
A1  - Krause, Felix
A1  - Schwotzer, Matthias
A1  - Nefedov, Alexei
A1  - Süssmuth, Julia
A1  - Haubitz, Toni
A1  - Kumke, Michael Uwe
A1  - Thissen, Peter
T1  - Hydrophobic Properties of Calcium-Silicate Hydrates Doped with Rare-Earth Elements
JF  - ACS sustainable chemistry & engineering
N2  - In this study, the apparent relationship between the transport process and the surface chemistry of the Calcium-Silicate Hydrate (CSH) phases was investigated. For this purpose, a method was developed to synthesize ultrathin CSH phases to be used as a model substrate with the specific modification of their structure by introducing europium (Eu(III)). The structural and chemical changes during this Eu(III)-doping were observed by means of infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), and time-resolved laser fluorescence spectroscopy (TRLFS). These alterations of the CSH phases led to significant changes in the surface chemistry and consequently to considerable variations in the interaction with water, as evidenced by measurements of the contact angles on the modified model substrates. Our results provide the basis for a more profound molecular understanding of reactive transport processes in cement-based systems. Furthermore, these results broaden the perspective of improving the stability of cement-based materials, which are subjected to the impact of aggressive aqueous environments through targeted modifications of the CSH phases.
KW  - Rare-earth elements
KW  - Europium
KW  - Luminescence
KW  - Metal-proton exchange reaction
KW  - Contact angle
KW  - Infrared spectroscopy
KW  - X-ray photoelectron spectroscopy
Y1  - 2018
U6  - https://doi.org/10.1021/acssuschemeng.8b03244
SN  - 2168-0485
VL  - 6
IS  - 11
SP  - 14669
EP  - 14678
PB  - American Chemical Society
CY  - Washington
ER  -